Process of briquetting finely divided coal, fuel, or other pulverulent materials



Patented Oct. 6, 1931 UNITED STATES PATENT OFFICE OTTO REYNARD, OFLONDON, ENGLAND PROCESS OF BRIQUETTING FINELY DIVIDED GOAL, FUEL, OROTHER PULVERULEINT MATERIALS No Drawing. Application filed March 15,1928, Serial No. 262,059, and in Great Britain April 4, 1927.

When finely divided coal or other fuel is briquetted with coal tar pitchor petroleum asphalt in the manufacture of briquettes, suflicientbinding material has to be used to 5 cover all the particles of thematerial to be briquetted with a film of molten binding agent.

' It is a matter of experience that from 7 to 10 per cent of bituminousbinding mateio rial has to be utilized to obtain satisfactory results,whereas it is a matter of calculation that less than 5 per cent istheoretically necessary to cover the entire surface of the fragmentaryfuel with the molten binder, taking into consideration the average sizeof the fuel particles and the viscosity of the molten agglomerant undernormal working condition. The excess of binder required is due to theinadequate wetting of fuel by molt- 2 en binder in ordinary practice,and results 1n a briquetted product which softens unduly and gives riseto unnecessary smoke when it is eventually consumed in a furnace.

The object of the present invention 1s to 135, provide means forimproving the quality of the finished product and reducing the quantityof bituminous binder employed to the amount which is theoreticallynecessary and is carried out as follows The fuel is intimately mixedwith from 3 to 6 per cent only of its weight of bitumlnous binder andbefore being introduced into the heated incorporatings-yessel, commonlyknown as the pugmill, there is added to 1t an aqueous emulsion whichcompnses:

1. An oil which has a natural aflinity for the bituminous binding agentemployed; and

2. An emulsifying agent which is capable of forming reasonably stableemulsions with the-aforesaid oil, and which is itself preferablythoughnot necessarily-a substance possessing adhesive properties.

The emulsions which are suitable for the invention are of thewater-in-oil type. The object and effect of adding such emulsions to amixture of fuel and bituminous binding material is twofold. First, theoil ingredient of the emulsion fluxes the bituminous base to 59 form aproduct of lower melting point and agents for finely divided viscosityso that a harder pitch or asphalt than could be used alone becomesavailable for briquetting, with consequent increased ease ofgrmding andincorporating with the pulverized fuel. Secondly, the emulsifying agent,which will generally be an aqueous solution, but which may also be apseudosolution or a suspension in water, induces the dispersion of waterin the asphalt or pitch, which is fluxed by the oil, when theemulsifying agent comes into contact with bitumen at a temperature of 80to 100 0., which is the normal range of temperatures to which the fueland binder are heated in the final mix ng process. This dispersion of.water in bitumen is an essential feature of the present invention andresults in increasing the volume and covering action of the agglomerant,which is thus compounded in situ during the final incorporation.

It has previously been proposed by various means, (a) to disperse waterin a bituminous base, or b) to emulsify bitumen in water, and to usethese compounded products as binding fuels, but the present inventiondiifers materially from these known processes. As regards (a), isspecial plant required to prepare such dispersions of water in bitumen,butthe resulting products are semi-solids which are tacky and diflicultto grind; moreover, they lose much of their essential dispersed water inthe course'of grinding.

Further disadvantages attending the use of such compounded binders, arethe very considerable costs'in power, labour, and plant upkeep whichthey entail, and the long period which must elapse between the time whenthe hot, plastic mass is first manufactured and the time when it issufficiently cool and consolidated to go through a disintegratingappliance without choking it.

As regards (b), the products which are known as bitumen emulsions areemulsions of bitumen in water in which the water represents thecontinuous phase of the emulsion. Such emulsions cannot be produced bythe methods of the present invention, which cause the dispersion ofwater in bitumen with the bitumen representing the continunot only ousphase, of the emulsion, which is momentarily produced when the variousingredients are brought together and heated in the final mixer.Furthermore an essential condition of emulsifying bitumen in water isthe use of bitumen which melts at about or below the boiling point ofwater, whereas an important feature of the present invention is the useof bitumens which melt at and above 120 C. and which are quite incapableof yielding emulsions in water by any known process.

It is therefore clear that the present invention does not refer to theuse either of a previously manufactured dispersion of water in bitumenor of a previously manufactured emulsion of bitumen in water, but referssolely to the use of emulsions of oil and water which are added to amixture of finely divided fuel and a bituminous material.

Mixtures of oils with solidifying or saponifying agents have been addedto fuel or road metal and pitch or other bituminous binding materials.

Emulsions suitable for the purpose oft-he present invention can be madei1rvar1ous ways, but these can be subdivided into two principal classes:

Class 1. Emulsions of water in oil are produced by the gradual additionwith thorough agitation in an emulsifying vessel, of any one or more ofthe following substances, pre viously dissolved in water, to heavypetroleum fuel oil, which may possess either an asphaltic or a paraflinbase: the chlorides, sulphates, nitrates, carbonates, or hydroxides ofthe alkali metals or of ammonia; the chlorides or nitrates of thealkalineearth metals; the silicates of the alkali metals.

Class 2. Emulsions of water in oil are produced by the same method as inClass 1, but instead of using solutions of mineral or inorganic salts,organic, colloidal solutions or suspensions are employed which possess ahigh degree of viscosity and which are themselves mostly substancespossessing adhesive properties. Typical emulsifying solutions are thoseof sodium caseate, gelatin or glue, sodium alginate, sodium pectate,sodium tannate or cellulose sulphite waste liquor, either in the acidstate or after neutralizing with caustic soda. Typical emulsifyingsuspensions are the pulps produced by boiling, preferably underpressure, cereals, such as maize, wheat, or barley, or tubers, such aspotatoes or beet, or vegetable growths, such as marine or fresh wateralgae, with sodium carbonate or sodium hydroxide.

The emulsions in question will generally comprise one part of fuel oilto from one to six parts by weight of aqueous solution or suspension,and the manner in which the invention is carried out for the purpose ofbriquetting finely divided fuel, is as follows The fuel is intimatelymixed with from 3 to 6 per cent of its weight of native asphalt,petroleum asphalt, or other pitch resultmg from the distillation of tarsor mineral o ls. This intimate mixture may take place either bypreviously grinding the said asphalt or pitch or by adding the latter ina molten condition. After this intimate mixture has taken place aquantity of emulsion, representing from one to four per cent of theweight of the fuel is added to the mixture. Both the mixture of fuelwith binder and the added emulsion may at this stage be cold. Theaddition of the liquid or pasty emulsion s made in such a manner thatthe emulsion 1S distributed throughout the mass of fuel as uniformly aspossible in the first instance and the three constituents, fuel, bitumenand emulsion, may then be subjected to a further cold rmxing process inan appliance such as a squirrel cage or other form of mechanical mixeror homogenizer, before passing into the final mixer in which heatingtakes placeprior to briquetting.

E mample 1 Anthracite was briquetted with 6% B1 petroleum asphalt,melting point 120 (1., 12% of emulsion comprising equal parts by welghtof Mexican fuel oil and a 20% soda ash solution.

Example .6

Anthracite was briquetted with 6% B1 petroleum asphalt, melting point120 C.. 1.8% of emulsion comprising one part of Mexican fuel oil to twoparts of a 5 11 solution of sodium caseate.

Example l l elsh steam coal was briquetted with 5% petroleum asphalt, mng point l-l0 6.,

of emulsion compris n equal parts of mean fuel oil and 2% sodiumalginate sciution.

E a'a/mple E wample 5 New Zealand Slack was briquetted with 6% B1petroleum asphalt, melting point 120 C., 1.8% of emulsion comprisingequal parts of Mexican fuel oil, cellulose sulphite waste liquor of 1.3specific gravity, and water.

All the above examples gave briquettes, pressed at 30 cwt. to the squareinch, which posesssed cohesions as determined by the Belgian drum testof from 85 to 90 per cent.

I claim novelty for a process of briquetting in which I bring together,during the stage when the constituents are incorporated and heated,immediately before they are moulded and pressed l. The fuel which is tobe briquetted;

2. lhe bituminous material-which is the binding agent;

3. An emulsion-which serves solely to increase the activity andefliciency of (2).

I do not claim the emulsions (3) as binding agents, which, for the mostpart, they are not.

ll do not claim that all the emulsions which I may use are novel, thoughmost of them are.

What I claim is the method whereby the emulsions (3), applied in themanner I described, cause a dispersion of Water 1n (2) at the momentwhen the mixture is prepared for briquettingsuch dispersion increaslngthe covering power, and therefore the cement ng action; of the bindingagent (bitumen) whlch is employed.

It is an esential feature of my invention that the emulsion shouldpersist unbroken and in its original liquid form until such time as ithas been added to the mixture of fuel and binding agent.

l claim 1. A process of briquetting cons1st1ng 1n mixing a finelydivided pulverulent material and a solid bituminous material and addingthereto an emulsion of the water-in-oil type comprising an oil having anaflinity for the bituminous material and an emulsifying agent capable offorming stable emulsions with the oil, and subsequently heating andpressing the mixture.

2. A process of briquetting consisting in mixing a finely dividedpulverulent material and a solid bituminous material and adding theretoan emulsion of the water-in-oil type e comprising an oil having anaflinity for t bituminous material and an emulsifying agent possessingadhesive properties and capable of forming stable emulsions. with theoil, and subsequently heating and pressing the mixture.

3. A process of briquetting consisting in mixing a finely dividedpulverulent material and a solid bituminous material normally melting atand above 120 C. and adding thereto an emulsion of the water-in-oil typecomprising an oil having an aflinity for the bituminous material and anemulsifying agent capable of forming stable emulsions with the oil, andsubsequently. heating and pressing the mixture. v 4. A process ofbriquetting conslsting in mixing a finely divided pulverulent materialand a solid bituminous material and adding thereto an emulsion of thewater-inoil-type comprising one part of an oil having an affinity forthe bituminous material and one to six parts by weight of an emulsifyingagent capable of forming stable emulsions with the oil, and subsequentlyheating and pressing the mixture.

5. A process of briquetting c0nsisting in mixing in a cold state afinely divided pulverulent material and from three to six per cent ofits Weight of a solid bituminous material and adding thereto from one tofour per cent of its weight of an emulsion of the water-in-oil typecomprising an oil having an aifinity for the bituminous material and anemulsifying agent capable of forming stable emulsions with the oil, andsubsequently heating and pressing the mixture.

6. A process of briquetting consisting in mixing a finely dividedpulverulent material and a solid bituminous material normally melting atand above 120 C. and adding thereto an emulsion of the water-in-oil typecomprising an oil having an aflinity for the bituminous material and anemulsifying agent possessing adhesive properties and capable of formingstable emulsions with the oil, and subsequently heating and pressing themixture.

7. A process of briquetting consisting in mixing a finely dividedpulverulent material and a solid bituminous material normally melting atand above 120 C. and adding thereto an emulsion of-the water-in-oi'ltype comprising one part of an oil having an affinity for the bituminousmaterial and one. to six parts by weight of an emulsifying agentpossessing adhesive properties and capable of forming stable emulsionswith the oil, and subsequently heating and pressing the mixture.

8. A process of briquetting consisting in mixing in a cold state afinely divided pulverulent material and from three to six per cent ofits Wei ht of a solid bituminous material and adding thereto from one tofour per cent of its weight of an emulsion of the water-in-oil typecomprising an oil having an affinity for the bituminous material and C.and addingmixing in a cold state a finely divided pulverulent materialand from three to six per cent of its weight of a solid bituminousmaterial normally melting at and above 120 C. and adding thereto fromone to four per cent of its weight of an emulsion of the water-inoiltype comprising an oil having an affinity for the bituminous materialand a emulsifying agent capable of forming stable emulsions with theoil, and subsequently heating and pressing the mixture.

11. A process of briquetting consisting in mixing in a cold state afinely divided pulverulent material and from three to six per cent ofits weight of a solid bituminous 1naterial and adding thereto from oneto four per cent of its weight of an emulsion of the water-in-oil typecomprising one part of an oil having an ailinity for the bituminousmaterial and one to six parts by weight of an emulsifying agent capableof forming stable emulsions with the oil, and subsequently heating andpressing the mixture.

12. A process of briquetting consisting in mixing in a cold state afinely divided pulvernlent material and from three to six per cent ofits Weight of a solid bituminous material normally melting at and abovet2U (l. and adding thereto from one to four per cent of its weight of anemulsion of the water-inoil ty )e comprising one part of an oil havingan a nit-y for the bituminous material and one to six parts by weight ofan emulsifying agent capable of forming stable emulsions with the oiland subsequently heating and pressing the mixture.

13. A process of briquetting consisting in mixing in a cold state afinely divided pulverulent material and from three to six per cent ofits weight of a solid bituminous material normally melting at and above120 C. and addin r thereto from one to four per cent of its weig it ofan emulsion of the water-inoil ty comprising one part of an oil havingan a nity for the bituminous material and one to six parts by weight ofan emulsifying agent possessing adhesive properties and capable offorming stable emulsions with the oil and subsequently heating andpressing the mixture.

In testimony whereof I have hereunto set my hand this 5th day of March.1928.

a OTTO REYNARD.

